on the broadcast tonight, moment of impact. why did a 777 passenger jet crash just barely on the runway in san francisco? tonight, what investigators are zeroing in on, the tremendous number of passengers who got out, and what first responders found upon arrival. the first video of what it's like inside. runaway train. the disaster still unfolding tonight to the north. an entire town virtually wiped out by a massive explosion. still so dangerous, they're having trouble searching for the missing. the defense in the george zimmerman trial calls trayvon martin's father to the stand. unexpected testimony days before the jury is expected to get the case. making a difference by helping a lot of young caped crusaders face their fears. "nightly news" begins now.

good evening. tonight in san francisco, investigators are narrowing in on what went wrong in the final ten seconds of a ten-hour flight across the pacific. while the death toll still stands at two tonight, two teenaged girls arriving in the u.s. for summer camp, it's also clear that a lot had to go right for so many people to walk away from the crash and the subsequent fire. we learned today in terms of forward air speed what it takes to keep a big jet in the sky. this one was barely creeping along as it barely made the end of the runway, clipping the tail on the rock seawall, the investigation now zeros in on what went so wrong right at this critical moment. our coverage begins tonight with tom costello. he is at sfo tonight. tom, good evening. >> reporter: hi, brian. good evening to you.

back there behind me on runway 28, that is what remains of flight 214 sitting there on the runway. we now know there were three captains on board this flight. one captain at the controls, brand new to the 777. brands new to the 777. 10,000 hours of flying hours in total, but he was being checked out by another captain. so that's very routine. the question tonight, what went wrong? emergency chutes are seen deploying in this new video taken just after the the crash of flight 214. moments later, passengers are seen running away from the burning aircraft as fire rescue crews pour foam on the fire. and new individual wrote of the crash itself. after ripping off its tail on the seawall, the 777 seems to jump into the air and nearly flip over before slamming into the ground. >> i thought before i left the plane it might blow up and i might die. >> reporter: today we got a photo of the teenagers from china killed in the accident. investigators are also looking

at whether one of them may have been hit by an arriving fire engine. on the ground today, notice investigators have been walking the length of the runway, inspecting a scattered trail of debris. the landing gear, sheared from the fuselage, and the interior of the plane itself, oxygen masks hanging, seats twisted and broken. >> the lower portion of the tail cone is in the rocks at the seawall. and there was a significant piece of the tail of this aircraft that was in the water. >> reporter: we learned today, the pilot, new to flying 777, and the training pilot allowed their airspeed to drop well below the 137-knot target for landing as they descended quickly. three seconds before the crash, the plane was stalling at just 103 knots, not a mistake you expect from veterans. >> there was a lack of interaction between the two pilots. the pilot that was actually manipulating the flight controls and the pilot who should be

monitoring airspeed and sink rate. >> reporter: the ntsb says it wasn't until 4 seconds before the crash that there were any system warnings of a stall. investigators plan to interview the crew in both english and korean to ask what was happening in those final seconds of flight, because both pilots were senior, did each assume the other was monitoring speed and altitude? nbc aviation analyst, former captain john cox. >> what was the demeanor of the inner worksings of the crew? how effective as a team? those are questions we need to have answers. >> reporter: investigators will also be trying to analyze what happened in the 72 hours before this crash. what were the pilots doing? how much sleep were they getting? was somebody sick? was somebody on medication? how much time were they on duty? all of that will play into analyzing exactly what happened in this accident. was pilot error to blame or something else? brian? >> tom costello, thanks. from the investigation to the survivors.

thankfully, there were many of them. we also hear from the first responders tonight. that part of the story from john yang in san francisco. >> reporter: when first responders arrived on the scene at runway 28 left, the threat was clear. >> jet fuel was leaking out of the plane, and our firefighters entered the plane, began a primary search, and began to extinguish fire. >> reporter: fire lieutenant chrissie emmonds got on to the plane the only way she could, running up the evacuation chute. she quickly found passengers trapped. >> when we first got back there and saw these people, it was actually pretty clear back there. there was not a lot of smoke, not a lot of fire. but by the time we removed the final victim, the fire was bank do you think on us. we had heavy black smoke. >> reporter: police officer jim cunningham had no protective gear and still rushed in. >> we were clearing the baggage because the overhead bins and all the luggage, half the things snapped and debris and rubble all over the place. >> one of the last on the plane,

a flight attendant attending to the remaining survivors. >> really brave. the crew, wanted to stay with the plane and make sure everybody was off. we kept telling them, get down, get down. >> reporter: the first responders managed to get few stranded on board to safety. only a few, thanks to passengers like ben levy who saw rescuers arrive as he helped other people escape. >> i just told people we're okay, come down, start getting out. leave your things behind, help each other. fairly quickly, a lot of people started going out through that door. >> reporter: today in china the distraught families of the two 16-year-old girls killed in the crash left shanghai for the united states. while in korea, survivors of the crash returned home to begin long and painful recoveries. in san francisco, the focus on men and women who answered the call to duty. >> we're the only cavalry that was there. nobody else was coming right away. we had to stand there and whatever we could do, we had to do it. >> reporter: risking so much to help so many survive. john yang, nbc news, san francisco.

on another front, the ntsb is also on-site tonight in alaska where the crash of a prop plane has killed ten people. the dehavilland otter sea plan crashed at a small airport about 80 miles southwest of anchorage. all nine passengers believed to have been from south carolina. one witness said the crash occurred on takeoff. in canada tonight, we're learning more about what may have led to a runaway train disaster, a huge explosion and fire over this past weekend. at least 13 people were killed initially. several dozen still missing tonight after tank cars filled with oil exploded in the center of a small town in quebec, not far from the maine border. nbc's katy tur is there for us tonight with the latest. katy, good evening. >> reporter: good evening, brian. investigators hoped to get to the heart of the blast today. they were finally able to do so. recovering more bodies, but with 37 still missing, this town is

bracing for even more bad news. moments after the crash, a towering fireball. new video shows the intensity of the flames. >> i saw the fire, a river of fire, go through the houses over there. i was quite nervous. >> reporter: it began around 1:00 a.m. saturday, seven miles northwest of lac-megantic when part of this 73-car train filled with crude oil suddenly started moving. a spokesman for the rail company says the train was unmanned at the time of the accident, parked for an overnight shift change when somehow a number of the tanker cars became detached from each other and then rolled straight into town. a gradual slope, the tanker cars picked up speed and then derailed. five cars exploded. at least 40 buildings were destroyed. >> i was supposed to be there. >> reporter: these women worked at the musey cafe in the heart of the burn zone. they described the friends that

they lost. as firefighters doused hotspots, hard questions about the safety of transporting crude by rail. it has seen a huge expansion in recent years. about 16 million barrels shipped by rail from canada to the u.s. last year, compared to an estimated 73 million this year, and nearly 110 million by 2014. >> the regulations we have for rail transport weren't designed to support rail moving massive amounts of oil. so it wouldn't be a surprise at all if our regulations weren't up to the task of what's happening right now. >> reporter: meanwhile, the scope of the tragedy in lac-megantic are still emerging, and the reasons why remain just as elusive as the identity of those lost. >> tomorrow will be another day. we lost people and we lost our downtown. we lost everything. you know. >> reporter: back out here live, you can see firefighters are still trying to stabilize the wreckage.

as for the why, why this all happened, there was a fire on board the train earlier in the evening. it's unclear if that had anything to do with the derailment an hour and a half later. this train was inspected on friday. they found nothing to be wrong with it. then again, just hours later, saturday morning, brian, there was the derailment. >> katy tur on this enormous disaster in canada tonight. katy, thanks. a deepening crisis in egypt this evening after one of the single deadliest days in that nation's recent history. despite that, the obama white house said today it does not intend to cut off aid to egypt at this point. there is an argument about how today's violence started, but at least 51 protesters killed. hundreds injured in a battle with the military. nbc's ayman mohyeldin in cairo tonight. good evening. >> reporter: good evening, brian. the removal of president morsi left egypt immediately divided and immediately led to violence on the street. today, things took a turn to the worse with a deadly confrontation that has many people fearing a new wave of bloodshed.

it was egypt's bloodiest day in more than two years of unrest. the clash between the military and supporters of ousted president morsi lasted for hours outside the republican guard compound where he is believed to be held. it left scores dead and each side blaming the other. the muslim brotherhood released this video. they claim it shows today's incident. a soldier can be seen firing from a roof into the crowd. an unprovoked massacre, they said, holding up military bullet casings and blood-drenched shirts. who do you blame for what happened here this morning? >> i blame the municipal defense. >> reporter: the military countered with its own video, appearing to show its soldiers coming under attack by what it called terrorists armed with guns and molotov cocktails. the military said it was acting in self-defense. a volunteer doctor treated hundreds this morning.

>> i think whoever was shooting them wasn't really wanting to evacuate the streets. it was really, um -- it was shoot to kill. >> reporter: morsi loyalists hate the army's commander. they are now calling for his trial. >> we want to judge him first, judge him by law, not in the streets. >> reporter: but that won't be easy. millions of egyptians wanted morsi and the muslim brotherhood out. the military is riding a wave of popularity. but many fear today's clashes will open a new round of violence between the army and the muslim brotherhood, which is not backing down. >> we'll increase the protesters. >> reporter: late tonight, egypt's president announced parliamentary elections and presidential elections would be held in seven months in an attempt to try and cool things down with the hopes that getting egypt an elected government will just do that.

brian? >> ayman mohyeldin in cairo, tonight for us. ayman, thanks. a couple more items in this country. a sad scene in prescott, arizona, this weekend. a procession of 19 hearses, all members of the same hot shot wildfire crew, trying to save the town of yarnell. the procession took five hours, traveling a route stretching 125 miles. tomorrow, the memorial service for all 19. teresa heinz kerry, wife of secretary of state john kerry, has now been upgraded from critical to fair condition in a boston hospital. she was airlifted from their summer home on nantucket island after exhibiting symptoms of a seizure. she is 74 years old. country singer randy travis hospitalized in texas in critical condition tonight with what we're told is a heart infection. randy travis is 54. there is a new tropical storm to let you know about in the atlantic. it's been called chantal.

warnings are up from barbados. a watch has been issued for puerto rico. and while there is a projected path for chantal, bringing it west toward cuba, forecasters warn it's still very early in the life of this storm. still ahead tonight, screams for help, but who was doing the screaming? a showdown in court over what trayvon martin's father heard on that 911 call.

at the trial in sanford, florida, george zimmerman's defense team started its first full day presenting its case. on the stand was trayvon martin's father. the point of contention today, what he heard on that 911 call. our report tonight from nbc's ron mott. >> reporter: today, defense attorney mark o'mara challenged trayvon martin's father about whether he told police the first time he heard the 911 call that it was not his son's voice screaming for help. >> i kind of pushed away from the -- away from the table and

just kind of shook my head and say i can't tell. >> reporter: martin told the prosecutor he later listened to the tape at the mayor's office some 20 times. >> basically what i was listening to, i was listening to my son's last cry for help. i was listening to his life being taken. and i was coming -- trying to come to grips that trayvon was here no more. >> reporter: earlier, the lead investigator offered a different version of martin's reaction to the 911 tape. >> i inquired if that was, in fact, his son yelling for help. >> what was his response? >> he -- he was more of a -- verbal and nonverbal. he looked away and under his breath, as i interpreted it, said no. >> reporter: one after another -- >> help! >> so you think he's yelling help? >> yes. >> reporter: five of zimmerman's friends testified they heard his voice.

>> yes, definitely it's georgie. >> i thought it was george. >> george. >> george zimmerman's voice. >> there is absolutely no doubt in my mind that is george zimmerman. >> reporter: witness john donnelly told the court george zimmerman is like a son to him, that he donated thousands zimmerman's defense fund, even bought the close zimmerman has worn to court. circumstances you agree there is a bias on behalf of george zimmerman because of friendship, correct? >> he is my very dear friend. >> reporter: zimmerman said he shot martin in self defense after being attacked. late today, the judge ruled that trayvon martin's toxicology report can be admitted. that report showed he had thc in his system when he died. thc, brian, is the active chemical in marijuana. >> ron mott in seasoned for, florida tonight. ron, thanks. we should point out george zimmerman has sued nbcuniversal for defamation, and the company has strongly denied his allegations. another break. we're back in a moment with the end of the drought on the grass

a lot of folks thought they would never see.

if you are a new york-based politician who has been involved in a sex scandal, time is running out to get on the november ballot. entering a local race that features anthony weiner running for new york city mayor after his meltdown. now former new york governor and call girl client eliot spitzer is running for new york city comptroller. he made the announcement just last night. easily the image of the day, this photo from china that is rushing water full of sediment, part of a project in china where they open gaps in an almost mile-wide dam in the yellow river to move silt downstream, to the town of 30 million tons of it a year. and when they open the dam, it becomes a spectator event. andy murray may never have to pay for a pint in great britain for the rest of his life. he obtained national hero status yesterday. he is on the front page of every british paper today, because he

broke the curse. even though the brits host wimbledon, no brit had won men's singles since 1936. his defeat of djokovic yesterday broke a 77-year-long drought. millions watched across the countryside. there is even talk of knighthood for the man from dunblane, scotland. and finally, what is easily the obit of the day. you'll forgive the phrase, but this item was buried in the columbus dispatch, announcing the death of scott entsminger. he was only 55 and lived in mansfield, ohio. and one line in it stood out. he respectfully requests six cleveland browns pallbearers, so the browns can let him down one last time. well done, scott. it sounds like a lot of browns fans we know. for the record, everyone has been asked to wear a browns jersey to his memorial service. up next tonight, making a difference by bestowing super hero powers on children who can use them.

finally tonight, our making a difference report, a program that helps kids with heart problems by injecting a little hero worship when times turn tough for them. it is appropriately called heart

heroes, and nbc's kevin tibbles has our making a difference report. >> let's check under the hood, bud. >> reporter: you would never know it, but mild mannered 6-year-old dylan rasmussen is a super hero. >> sounds good. >> reporter: and a good thing too as the past year has not been easy on dylan and his family. born with a congenital heart defect, he had to undergo open heart surgery. >> it was really hard to let him go back. >> reporter: dylan confronted his illness like a man of steel. >> we got him a cape that was made especially for him. >> reporter: a shiny silk cape from heart heroes. a group that provides kids with heart defects a boost, while battling forces beyond their control. >> they don't have to worry about the disease, the hospital visits. they can just be a super hero. >> it was devastating. >> reporter: kitty and sandra founded heart heroes when their own children faced

life-threatening heart problems. sandra's daughter ashley is now 12. >> makes you feel brave. >> reporter: kind of takes you back. putting on one of these as a kid really made you feel like you had those super human comic book powers. well guess what? some of the powers are real. >> the cape doesn't help me reroute the vessels, but for the child to go into the operation feeling brave, it's -- it lets them think about their experience with a positive attitude. i did it, i can do it. >> reporter: and the good thing, those powers also rub off on the parents. >> when we were going through our darkest times, any little thing was what we hung on to. >> all right. good. >> reporter: for a kid facing down the darkness, it's good to know that you and your doctor can leap tall buildings together. kevin tibbles, nbc news, chicago. and that is our broadcast on a monday night as we start a new week. thank you for being here with us. i'm brian williams, and we hope to see you right back here tomorrow evening. good night.